Residential and commercial water consuming and water treating appliances are almost universally now required, for installation, to conform to one or more local or state plumbing codes such as IAPMO Uniform Plumbing Code, ICC International Plumbing Code, BOCA or SBCCI. These codes require using a sufficient “air gap system” for safe drainage of waste water from a water treatment appliance to a house main drain or sewer pipe. The air gap is typically provided by a specially designed plumbing fixture or hardware that connects the outlet of the appliance drain line to the inlet of the sewer pipe, and in doing so provides an opening that forms an “air gap”, i.e., the vertical distance through the atmosphere between the lowest potable water connection outlet and the highest level of the source of fluid contamination. The air gap device thus ensures a point of separation of potable and non-potable conduits in the overall plumbing system. Such an air gap installation thereby avoids a direct drain connection to a sewer system, a so-called “cross connection”, that otherwise would provide a risk of contamination when a sewer backs up or when there is a loss of pressure in the fluid supply or water supply side of the system. This may occur, for example, when a system pump fails to run and thereby causes a back-siphon effect that in turn causes water flow from the sewerage system into the house's potable water system. A fire fighting pumper can also cause a suction in the water supply system that in turn causes water to be sucked back up from the sewer system.
In addition, in order to accommodate the greater pressures and flow rate requirements from the latest high-capacity water softeners and commercial reverse osmosis filtration systems, some local and state plumbing codes now often dictate that a rigid Schedule-40 line be plumbed to the air gap and drain line of the appliance in order to accommodate the greater pressures and flow rate requirements from these more recent appliances providing a more solid and failsafe connection. Moreover, despite the abundant types and designs of various air gap fittings available on the market, a new design for high flow rate Schedule-40 stand pipe air gaps has been requested by numerous plumbing supply houses, plumbing contractors and water treatment equipment installers around the country and abroad as a result of the new high-performance “Dual Head” water softener controls with high discharge rates. Appliance manufacturers have not been provided with the necessary plumbing drain connection fittings to satisfy the plumbing codes in many locales. This situation has lead to the installer creating some kind of on-site connection that will get the discharge water into the drain, but will not in many cases, depending upon the plumbing inspector and local plumbing codes, pass the required plumbing inspection to meet the applicable code.
The prior art is replete with various plumbing fittings designed to serve an air gap function. One example of an improved tubular air gap product is the Model DLA-G manufactured and sold by Eco-Tech, Inc. of Rogers, Ark. and disclosed and claimed in U.S. Pat. No. 5,681,459 issued Oct. 28, 1997 and naming as inventor the inventor herein, Dennis E. Bowman and illustrated in FIGS. 36-38 thereof. The Model DLA-G is a tubular product designed for connection of the outlet end of this air gap fitting to Schedule-40 pipe by way of a male Schedule-40 trap adapter using an S.J. nut and washer. However, the inlet of the DLA-G air gap fitting is designed to receive only various sizes of tubing, typically reverse osmosis and water softener waste water drain line tubing.
Another example of a prior air gap fitting for Schedule-40 drain pipes is that shown on the web site www.abetterairgap.com on page 3 of the product information section and identified as the “BA2 Air Gap”. However, this design fails to meet the needs now satisfied by the air gap constructions of the present invention as disclosed hereinafter.
Accordingly, among one or more of the objects of the present invention is to provide (1) an improved air gap fitting that will function as a drain line adapter connection to a rigid Schedule-40 stand pipe drain, i.e., an ABS or PVC Schedule-40 standpipe having an outside diameter (O.D.) of either 1½ inches or 2 inches; (2) an improved air gap fitting designed to the strict tolerances of the appropriate ASTM standards governing ABS Schedule-40 fittings; (3) an improved air gap fitting having an easy hold hex head to receive a wrench to rotate the fitting or resist rotation of the fitting as needed, (4) moldable in one piece from durable ABS or PVC plastic; (5) an improved air gap fitting available in inlet inner diameters (I.D.) of ½ inch, ¾ inch or 1 inch and provided with national pipe thread (NPT, e.g., FIPT) standard female threads in the inlet to thereby readily accommodate various conventional plastic, copper, brass or steel adapter fittings typically provided as shelf items for connecting to the air gap fitting when installing the same on a rigid Schedule-40 drain pipe; (6) an air gap fitting having an inner drain tube with an air gap side opening having a vertical extent of at least 2 inches and oriented so as to be rotated 180° away from a single outer air gap window side opening in the fitting hood that also has a vertical extent of approximately 2 inches and is vertically at the same elevation as the inner tube air gap opening to thereby accommodate high flow rates without splashing liquid out of the air gap; (7) that can be telescoped at its outlet end over a 1½ inch ABS or PVC stand pipe and adherently affixed thereto using ABS or ABS/PVC cement, and also can be telescoped to slip into and telescope inside an ABS or PVC vertical 2 inch Schedule-40 drain waste and vent (DWV) coupling hub fitting; (8) the easy hold hex head protrusion at the inlet end of the fitting is made with an outside dimension large enough to accommodate forming either ½ inch or ¾ inch I.D. female threads in the inlet opening; and (9) a full 360° circular interior ledge recessed axially inwardly from the outlet end of the air gap fitting to provide an accurate and rugged slip-stop for the air gap when it is being installed telescopically over the outside of the inlet end of the drain pipe.